The present invention relates in general to the internet and in particular to methods and systems for accommodating roaming endpoint users across H.323 compliant network domains.
The internet comprises an interconnected set of networks where the individual networks may use various protocols within a specific network but which use standardized internet protocols (IP) for communicating with other networks.
While the internet started with the idea of transmitting only text, the protocol has expanded to many types of media including voice, video and other graphics. The communication is in the form of packets of data and thus there is no solid or fixed connection as is the case with the public switched telephone network system (PSTN). In general, when an internet user wants to communicate with another user, the sending party transmits a message to the internet service provider (ISP) of the recipient. The recipient obtains the communication when he next accesses the ISP and requests any previously unreceived messages. Two way communication of either voice or text requires an advance arrangement on the part of both the sending party and the recipient to be accessing the internet and using the appropriate protocol.
In an attempt to simplify internet communication problems, various standards have been formulated and adopted in the industry. These standards are followed when designing new hardware and software. An example is H.323 entitled xe2x80x9cPACKET BASED MULTIMEDIA COMMUNICATIONS SYSTEMSxe2x80x9d which is incorporated herein by reference. Standard H.323 covers the technical requirements for multimedia communications systems in those situations where the underlying transport is a packet based network (PBN) which may not provide a guaranteed quality of service (QoS). The H.323 standard covers not only calls between H.323 compliant terminals in remotely located H.323 compliant networks, but also covers calls between such terminals and telephones in switched circuit systems such as the PSTN. For the purposes of this invention, a call is defined as a multimedia communication between two terminals at least one of which is H.323 compliant. The call may comprise the use of a collection of channels between terminal endpoints some of which channels may be xe2x80x9cunreliablexe2x80x9d. In accordance with terminology in the art, a xe2x80x9creliablexe2x80x9d channel uses a protocol that keeps track of the number and order of messages sent and received so that the receiving endpoint knows when data packets are missing or received out of order. An unreliable channel merely delivers message packets as well as it can but requires the sending program to worry about whether or not any messages are received at the destination and whether or not received messages are received in the proper order. As will be obvious to one skilled in the art, an unreliable channel will normally provide much faster communications of a given quantity of data than would a channel that must also continually communicate data tracking messages.
Such a call as defined herein begins with a call setup procedure and ends with a call termination procedure. Other examples of standards applicable to calls incorporating the internet are H.225.0 entitled xe2x80x9cCALL SIGNALING PROTOCOLS AND MEDIA STREAM PACKETIZATION FOR PACKET BASED MULTIMEDIA COMMUNICATIONS SYSTEMSxe2x80x9d, H.235 entitled xe2x80x9cSECURITY AND ENCRYPTION FOR H SERIES (H.323 AND OTHER H.245 BASED) MULTIMEDIA TERMINALSxe2x80x9d and H.245 entitled xe2x80x9cCONTROL PROTOCOL FOR MULTIMEDIA COMMUNICATIONSxe2x80x9d. The H.225.0, H.235 and H.245 standards are also incorporated herein by reference.
To date, the standards and the industry practice have been directed to communications between users accessing terminals at known locations in their home network. While generally, users must check the network to see if any communications are being held for the user, systems exist that notify a user that there is mail in the mailbox when a user""s terminal is turned ON. Further, if the user""s terminal is already turned ON, a display or a speaker of a terminal can advise the user that a communication, whether electronic mail or a voice call, is being received. The H.323 standard referenced above includes voice and other multimedia calls set up and completed between a H.323 compliant terminal and another terminal where the recipient H.323 compliant terminal user is located in that users xe2x80x9chomexe2x80x9d network.
Users are often required to travel to remote sites for extended periods of time and while at the remote site may have access to a terminal on a different network from that users home network. It would be desirable to have a system and method for automatically and seamlessly forwarding voice and other communications, originally directed to a users terminal at a home network, to a terminal at the remote site after a user contacts a home network and forwarding is authorized. While such an action would be comparable to roaming users in cellular phone technology, the differences in basic construction of the internet and the telephone system prevent any direct correlation in processes to accomplish such authorization and forwarding of communications.
The present invention is directed to the method of and apparatus for completing multimedia calls over a packetized data transmission link to a roaming user currently located in a network foreign to the users home network.